This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. With the increased sophistication of new methods of pulsed dipolar spectroscopy (PDS), currently under development and the need to test them on the bench, we need to design a "flight simulator", i.e. a bench-test system to generate "stimuli" for receiver, signal processing, and pulse generation. Such system will use a home-built waveform-generator, which will simulate echo based on input phase and pulse sequences, which will be decoded in FPGA according to downloadable look-up tables. The system will also include standard noise source for receiver noise figure testing and calibrated pulse source for receiver gain testing. The unit will be controlled by a dedicated PC host running intuitive LabView interface.